Service chaining differentiates forwarding of traffic flows across a policy-defined ordered set of middle boxes (also commonly referred to as services, inline services, appliances, network functions (or virtual network functions in the case of network function virtualization (NFV)), or service functions (SFs)). Examples of SFs include firewalls, content filters, intrusion detection systems (IDS), deep packet inspection (DPI), network address translation (NAT), content caches, load-balancers, wide area network (WAN) accelerators, multimedia transcoders, and logging/metering/charging/advanced charging applications.
Service chaining requires a classification process to assign traffic to the correct service chain, followed by differentiated forwarding/routing of the traffic flow across the correct set of SFs (e.g., a service function chain (SFC)). The Internet Engineering Task Force (IETF) is developing protocols that will allow more efficient ways to implement SFCs. The IETF is also working on defining a network service header (NSH) that is added to packets to assist with service chaining. Then service function forwarders (SFFs) will create the service function paths (SFP) in the form of an overlay. Such service chaining is applicable to both physical network functions and virtual network functions (vNF).
Network measurement provides a network operator with data that enables the operator to characterize the state of the network, the traffic demands, the actual consumption of network resources, and the performance of the network experienced by end users. The network operator can use this information to optimize the usage of network resources in the network. Network paradigms such as software defined networking (SDN) and network function virtualization (NFV) can be used to achieve a holistic view of network and cloud resources.
The amount of network resources and cloud resources (e.g., central processing unit (CPU) resources, memory, bandwidth, storage) that an SFC utilizes can vary depending on the specific SFs (e.g., vNFs) included in the SFC, the amount of traffic in the network, and other factors. Also, the amount of resources required by an SFC can change over time as circumstances change. Existing solutions for provisioning SFC resources are based on static rules and policies. Static rules and policies usually either over-provision resources (leading to inefficient use of resources) or under-provision resources (leading to performance degradation).